Activist investor Elliott Management Corp. called for change at Cognizant Technology Solutions Corp., a $34.6 billion IT-outsourcing firm whose growth prospects have been upended by the rise of cloud computing.

Elliott said Monday it held a 4% stake in the company worth $1.4 billion—the fund’s largest-ever initial stock purchase for an activism campaign, according to FactSet. In a 16-page letter, Elliott said Cognizant should boost profitability and return cash to shareholders instead of focusing on revenue growth.